There are many known devices used as laser sighters for weapons, particularly pistols. It has, however, been difficult to develop a suitable laser sighter for small pistols (such as those that fit into one's pocket) because there is very little available space on the side or top of the gun to mount a laser, and mounting it to a trigger guard can be difficult plus the laser can be jarred out of position. Moreover, mounting a laser in any of the above positions on a small pistol may make the assembled pistol and laser hard to conceal, or fit within a pocketbook or pocket, which defeats its purpose.
Therefore, for these applications the laser has typically been mounted in a casing (preferably made of plastic) positioned in front of the trigger guard in order to minimize the additional size of the assembled device. The problem, however, is that for virtually every make and model of gun, a different laser assembly configuration is required because of the different gun configuration. Hence, a manufacturer may require to manufacture and inventory, and dealers may have to inventory, dozens (or more) of different laser assembly/casing units to fit each type of small pistol. This increases manufacturing and inventory carrying costs. Plus, there is a greater possibility that the manufacturer or dealer will have too much of one type of laser assembly/casing unit and not enough of another.
Additionally, there are laser sights used with a gun when firing bullets, and laser trainers, used with a gun when, instead of firing a bullet, when the firing pin is activated, a laser light beam is generated.